Role of codec selection on the performance of IPsec secured VoIP

摘要

Current research works have looked at improving the IPsec secured VoIP by arbitrarily increasing bandwidth which is a very limited resource and cannot just be increased in real environments except under laboratory conditions. Also, in most earlier works, codec has been kept constant and the IPsec impact analysed. The results of such works undoubtedly show the devastating impact IPsec has on VoIP which cannot be generalized because much attention has not been given to bandwidth utilization of the IPsec secured VoIP through the proper choice of codecs. In this paper, we have quantitatively justified the impact of IPsec on VoIP in terms of packet loss, jitter and MOS percentages in scenarios where a high bandwidth consuming codecs such G.711 is used as well as scenarios for Speex, a low bandwidth codec. Our results show that irrespective of the impact of IPsec on a VoIP network in terms of packet loss and jitter, a better choice of codec enhances quality of voice output and there would not be the need to arbitrarily increase bandwidth.